At present, aluminum alloy wheels are manufactured by mainly adopting a low-pressure casting production process. Due to the fact that the whole mold system is always located in a relatively open atmospheric environment and due to the easy oxidation characteristic of aluminum alloy, oxidation slag inclusion becomes one of common defects of wheel castings. Such defect causes reduction of the density of product organization and weakens the integrity of castings, the mechanical properties and service life of wheels cannot always meet the using requirements of clients, meanwhile the defect is not easily found through X-ray inspection, and therefore, great harm is brought. In actual wheel production, air in a cavity is generally exhausted as much as possible by arranging an exhausting plug at an inner rim of a top mold and scribing mark lines so as to reduce the oxygen degree of molten aluminum, but it is actually proved that the effect is not obvious.
Based on the above analysis, the problem of air residue in the cavity is required to be fundamentally solved for better decreasing or even eliminating the oxidation slag inclusion defects produced in aluminum alloy wheel production, a good environmental atmosphere is created for molten aluminum alloy mold filling by adopting some effective means, and it also becomes a significant problem to be solved by engineering technicians.